Mechanisms
by OxEyed
Summary: Form and function are not identical. Beauty and fear are not exclusive. Post-series; Crushshipping oneshot Tristan x Serenity x Duke . Written for Yugioh FanFiction Contest Season 10.


The floating platform was smaller than the camp's main dock, but it still had plenty of room for the half-dozen kayaks, and two rowboats that occupied it. On one end, two small fishing boats rocked back and forth, bumping into each other whenever a particularly strong wave came along. The other end of the dock faced away from the camp and provided a pristine view of both the bay and the stars.

Serenity carefully made her way around a pile of oars and life jackets. While the repeated beat of the water against the dock made a pleasant swooshing sound, she wasn't used to the motion and lost her footing more than once in the darkness. When she reached the edge of the dock, she sat down, careful to not drape her legs over the edge. Despite it being mid-summer, it was a fifty-some degrees out and the water was sure to be freezing.

Her solitude lasted only a few moments. A single flashlight beam was approaching slowly from the shore. When the distant voices of her companions became so clear she could make out their words, she turned around. She couldn't see the two people making their way down the ramp, but the irritated lilt of their raised voices made identifying them easy.

"I didn't _say_ it was a better idea, you dolt. At least, not to _you_. And why are you eavesdropping on-" The slam and muffled curse words that followed indicated that the speaker, Duke, had slid on the end of the ramp, which was slick with seawater even in July.

"No one invited you," Another voice cut in: Tristan's. The flashlight swung toward the bottom of the ramp when he spoke. "If you think it's going to be so 'dull', why don't you go back and make s'mores with everyone else?"

"Because I hate smoke. And s'mores. And for the last time, Tris, point the flashlight where I'm walking, not in my face. How am I supposed to see anything when you keep-"

"Where'd Serenity go?" Tristan had reached the bottom of the ramp, and was swinging the flashlight around erratically.

Serenity raised her arm above her head and waved. "Over here, guys."

Their argument abruptly over, the two boys made their way toward her. Serenity leaned back on her palms and watched their progress, trying not to laugh when they collided with pieces of boating equipment.

Duke, despite all his complaining, made it first and flopped down beside her.

"Heya," he said, his teeth flashing white in the darkness. "Nice out, isn't it?"

"It's very pretty," Serenity said. "I've never seen so many stars in my life. And it's so quiet."

"Quiet" was an understatement. The camp was miles away from any kind of civilization, accessible only by boat or seaplane. A radio link to a nearby fishing port served as their only means of communication with the outside world. The generator had already been turned off for the night, and altogether it was the closest thing to perfect silence Serenity had ever experienced.

"Are you cold?"

Surprised, Serenity glanced at Duke. "Huh?"

"It's cold out," he repeated. "And you're only in a t-shirt. You want my jacket?"

Serenity had left her own coat behind. It had been too warm by the fire, and she had wanted to enjoy the night air. "I'm really fine…"

Duke had already started shrugging out of his jacket. "Don't worry about it," he said. "Here. It's leather, so it holds heat pretty well."

She didn't want to make a big deal about it, so Serenity slid the sleek black coat over her her shoulders. It was too big, she thought, brushing her fingers over a pattern of red diamonds that ran down the front, but it was comfortable. That it had the distinct smell of Duke was a nice bonus.

When she turned to thank him, his attention was elsewhere. "What the hell is Tristan doing?"

Serenity looked back. Tristan had stopped halfway down the dock and was peering into the water.

"Dude," Duke said, raising his voice slightly. "What are you looking at?"

Tristan glanced up and automatically swung the flashlight toward them. Both Duke and Serenity held up a hand to shield their eyes, and Tristan swung it back down, lurching away from the edge and toward them.

"Nothing," he said. "Fish."

When he arrived at the end of the dock, he surveyed the scene for a long moment.

The light prevented her from seeing Tristan's face, but Serenity could imagine his expression. Without thinking, she had sat in a corner. There was a kayak behind her and Duke was on her other side. Tristan, who no doubt wanted to sit by her, would have to either move the kayak or get Duke to move. Either move would be embarrassing.

She sighed in relief when Tristan switched off the light and sat next to Duke. While she loved both boys, the constant rivalry over her attention had long since run its course. Though she did feel sorry for Tristan: he had been the one to ask her down to the dock in the first place. Duke, overhearing them, had promptly invited himself. Serenity had said she didn't mind, but she did. She might have even preferred it if Duke hadn't come. Not because she preferred Tristan's company, but because Tristan, for all his constant grumbling, knew how to be quiet.

"So tell us again why you wanted to come down here." Duke laid down, crossing his arms under his head. His t-shirt rode up, revealing a pale sliver of skin in the moonlight.

A night like this deserved quiet.

"I thought'd it be nice," Tristan said sourly, twisting to get a better look at Duke. "Be nicer without you and your big mouth."

Snuggling further into Duke's coat, Serenity bit back another sigh. She knew Duke could be quiet-she had caught him, on occasion, paused over a game or a newspaper or even once the chalky outline of a hopscotch game, lips pursed and hands clenched, every muscle poised in tense inaction-but where Tristan was concerned, Duke couldn't sit still.

"Take it back." Duke said, sitting up on his elbows. He lifted a leg to jab at Tristan with his foot.

Tristan pushed it away. "No."

"Take it back." Jab, jab.

"Can't take back the truth."

"What?" Duke lowered his leg and rolled toward Tristan. "That's not true."

"Ask Serenity," Tristan said. It was a challenge, and one Duke couldn't resist. He sat up and leaned toward the girl in question, his chest against her shoulder. His mouth was almost touching her ear as he spoke.

"So, gorgeous? Be honest, would it be nicer if I wasn't here?"

Behind him, Serenity could barely make out Tristan's pained expression.

"What I think Tristan is saying," she said slowly. "Is that you're ruining the mood. Just because, you know, it's such a nice night out."

Duke recoiled, hissing through his teeth. "Shot through the heart," he said. "After I lent you my jacket, too."

"I noticed," Tristan said. "What's that about?"

"She was cold," Duke threw an arm around Serenity's shoulder. "So like a proper gentleman, I warmed her up."

Tristan bristled, but didn't reply.

"Are you jealous, Tris?" Duke said. "I bet you never got a pretty girl to wear _your_ jacket."

"How could I be jealous?" Tristan said. "Your jacket's so tacky you'd have to pay someone to wear it."

"Serenity wore it."

"Then she's tacky, too."

Serenity opened her mouth to comment and found herself absolutely speechless. Somewhere out on the water, something splashed. Then two things happened.

The first was that Tristan started to apologize. "Oh god Serenity I didn't mean that, you could make anything look good it's just Duke, you know, has that stupid sense of fashion and just shit I'm so sorry-"

Serenity tried to answer, but she was having trouble because Duke was laughing, and violently. His whole body was shaking as he buried his head in her shoulder, muffled outbursts of merriment punctuating Tristan's words like gunshots.

When Tristan realized what was happening, his embarrassment turned to anger. "Stop laughing!" He pulled Duke away from Serenity, but Duke just fell back against Tristan. When Tristan tried to punch him, Duke held onto Tristan's shoulder and laughed harder. Nothing Tristan did could make Duke stop laughing, and after a fruitless scuffle, he said, "Well, you asked for it."

Then Tristan pushed Duke into the water.

Serenity didn't even have time to react before Duke surfaced with a scream that could have woken the entire camp.

"TRISTAN, YOU SON OF A BITCH!"

Tristan was laughing, but Serenity's attention had been captured by something else. When Duke had fallen in, the water around him had lit up in a bright blue that slowly grew and ebbed with his every movement.

Duke had also noticed the lights. When he saw the glow that surrounded him, he shrieked and pulled himself onto the dock, bringing a significant amount of seawater with him. Shivering, he stood up and stepped back, glaring suspiciously at the water. "What the hell was that?"

"Plankton," Tristan said, laughing. "What, were you scared?"

"No!" Duke's jeans squelched as he bent over to take off his shoes and socks. "Asshole."

"Plankton?" Serenity asked. "Why do they light up like that?"

Tristan shrugged. "The camp director told me about them. I just know that when you disturb the water, they light up. Some kind of, um, protection thing."

"It's called a defense mechanism." Duke said. He pulled off his shirt and wrung it out. His entire body shook visibly in the moonlight. "Can't believe you did that," he muttered. "The water's freezing."

"You deserved it," Tristan said. Duke snapped his wet shirt toward him, but the action was halfhearted.

"Are you okay, Duke?" Serenity said. "You should go change."

Duke looked up. His hair was plastered to his face and neck, and he pushed it aside to grin at her. "I'll be okay, hon. Gotta get Tristan back first."

"Not gonna happen," Tristan said.

Duke didn't contest the point. Sitting down on an upturned kayak, he ran his hands through his hair and started to squeeze out the water. The kayak wasn't very sturdy, and rocked back and forth every time he moved.

Serenity turned to Tristan. "Give him your coat," she said.

"What?"

"You threw him in," Serenity said. "Seems like the least you could do."

"Serenity, I'm fine-" Duke said.

"Shut up, Duke." Serenity snapped. Both boys froze.

She only needed to stare at Tristan in frigid silence for two seconds.

He sighed. "Fine, fine, whatever." He stood up and pulled off his coat. He offered it to Duke, who took it without comment.

Serenity got up and joined them, ignoring the tense hunch of Tristan's shoulders when she approached.

She must have opened and closed her mouth a dozen times, trying and failing to come up with a satisfactory rebuke. She wasn't even sure who she was more annoyed with.

Duke didn't put on the coat. He sat rigidly on the kayak, clutching it in his hands. He didn't look at either of them.

Then Tristan rolled his eyes. "All right, fine," he said. "I'll jump in, too."

Duke lifted his head.

"What?"

"That would fix it, right?" Tristan said impatiently. "If I jumped in?"

The proposition seemed to make Duke angry, and he leaned forward, clutching Tristan's coat like a weapon. "I said I'm-"

Serenity put a hand on Duke's shoulder. His skin was clammy. "_I_ might feel better," she said. "If he jumped."

Duke's muscles twitched under her hand. "That's-

"I want to see those lights again."

After a long, loaded moment, Duke relaxed. "Fine," he said. "But you have to scream when you do it. Like a girl."

Tristan snorted. "I'm not doing that."

"Hey man, you offered."

"I offered to _jump_, not make a fool of myself."

"I think it's a fair request," Serenity said. Tristan might have glared at her; she wasn't really sure in the dim light, but he turned away from them to contemplate the water.

Several seconds of silence followed.

"The longer you wait," Duke offered helpfully, "The harder it's going to be."

"Shut up," Tristan said. He bent down to pull off his shoes.

Duke had started to lean against Serenity. She didn't realize it until she shifted her weight and he jerked away with a mumbled apology.

She hesitated, then pulled him closer.

Tristan was staring at the water again. "I'm really going to regret this."

"Should have thought of that before you pushed me in," Duke said. "Now hurry up. I want to go take a shower before my hair is permanently ruined."

Serenity laughed, and Tristan glared at them. "Fine, fine," he said. "You better pay attention. I'm only doing this once."

Then, with a shake of the shoulders and a horrible banshee yell, Tristan made a running leap off the dock, his voice rising in volume and pitch until he hit the water with a splash large enough to spray both of his audience members.

Same as the first time, the water lit up like magic, and Serenity and Duke leaned forward to watch it grow and ebb with the strokes of Tristan's arms.

The effect was slightly ruined by Tristan's frequent shrieks about the temperature of the water. Despite Serenity's protests, he swam back to the dock and pulled himself out immediately.

"If you want to see the lights again," he growled, "You can jump in yourself."

"That's not very gentlemanly," Serenity said. Duke threw his head back to laugh.

"Well, you heard him earlier," he said. "He thinks you're tacky."

"That's not what I said!"

"Ah," Serenity said. "That's right, he did. Looks like Duke wins my heart."

"I'm going to throw you both in next time," Tristan said, shuddering.

"He's just getting less chivalrous as the evening goes on, isn't he?" Duke said. "Now we see his true colors."

In answer, Tristan pulled Duke off the kayak and into a sloppy headlock. "I'll show you true colors!"

"Tris, let go! You're _soaking_!"

Serenity shook her head and smiled. "You guys need to get changed. Let's go back."

Tristan let go of Duke and they both gathered their clothes quickly. As they started up the ramp, Serenity had an idea.

"If you want, I'll meet you two in the kitchen," she said. "And I'll make us something warm to drink."

"That sounds _amazing_," Duke said. "You, Serenity, are an angel on earth."

"That's laying it on too thick," Tristan muttered, flipping on the flashlight and shining it dutifully on the path ahead.

"Oh yes, and you're Mr. Romantic over here. My jacket is not tacky, thank you, and even if it was, Serenity could make it look good."

"Would you drop that?"

"Words are a reflection of the heart, Tristan."

"Well then get ready for an ass-kicking, because that's what's in my heart right now-"

The flashlight bobbed as Duke and Tristan got into another scuffle and Serenity continued on without them. They were almost to the cabins, and just beyond, the light of the campfire was enough to light her way.

The bleachers around the fire pit were mostly unoccupied by this point; a lot of people had gone to bed when the generator was turned off. Joey and Mai, deep in conversation, were the only ones left.

Smiling, Serenity skirted the area so they wouldn't see her and continued on to the camp kitchen. There was no electricity, but there were a few flashlights sitting on the counter. Serenity turned two of them on and stood them on their ends so they were facing the ceiling. Poor lighting, but it was better than nothing. She took the third flashlight and used it to find a kettle.

The stove was an old one, so she turned on the gas and ignited it with the lighter hanging on the nearby wall. After putting a kettle on the stove, she began looking for hot chocolate. There was some bagged tea under the counter, but nothing else. She headed to the pantry, where several minutes of looking yielded no results.

Serenity didn't mind. Without the boy's company, she could still think in peace.

Before long, the crunch of gravel warned her of someone's approach. Serenity peeked out the pantry as Tristan pushed open the screen door and stepped inside, the flashlights framing his silhouette when he paused by the counter.

"Serenity?"

"Over here," she said, waving the flashlight up and down to identify her location.

"I'm looking for hot chocolate," she said. "I thought I saw some in here this morning, but now I can't find it."

"They took it out earlier," Tristan said. "When they made s'mores. I think it's out on the tables."

Serenity pointed the flashlight over the serving bar to the dining area, where several circular tables had been pushed together. Coats and board games were scattered everywhere. One of the coats, she knew, was hers.

She made her way to the tables, locating what she wanted quickly.

When she returned, Tristan was leaning on the stove, watching the flame beneath the kettle jump up and down. Serenity sat the hot chocolate down and joined him.

"Where's Duke?"

Tristan didn't look away from the flame. "Shower."

"In the dark?"

"I gave him my flashlight."

The conversation lapsed into silence. Tristan fidgeted for several moments before he took a deep breath.

"Hey, Serenity-"

"Don't," she said.

He forged on. "If you like him-"

Serenity pushed herself away from the counter. "I said don't, Tristan."

He tensed at her sudden movement. "I just-"

"If I told him," Serenity interrupted. "Would you two stop fighting?"

"What?" Tristan straightened a little to look back at her, but she didn't feel the need to repeat herself, and he grimaced, turning away. "Is that all you care about?"

"Just answer the question."

One shoulder moved up, then back down. "I guess," Tristan said. "I mean, yeah, probably."

"Because you would leave."

"Well, obviously."

The news makes Serenity feel a rush of anger. Then she saw the rigid arc of Tristan's back.

"Why do you always assume that someone else is better than you?" she said. "This isn't about better or worse. You both have different strengths and different flaws."

Tristan laughed and turned to face her. "What kind of excuse is that?" he said. "You don't have to worry about hurting my feelings, Serenity-"

"I like you too, idiot!"

Tristan went still, and Serenity hissed in frustration. She started to pull out coffee mugs, banging them around as loudly as she could.

"Sorry," she said. "But really." The kettle started to whistle, and Serenity snapped the gas off. "Why can't I like both of you?"

"Things don't work that way," Tristan said finally. "You'll have to pick someone sooner or later."

"Why do I have to pick?" she asked. "I don't want you to leave. And I don't want Duke to leave. Do you?"

"No!"

Serenity paused, a cup held in midair. "So," she said, placing the cup down. She turned toward Tristan. "Do you like him?"

Tristan wouldn't meet her eyes. His voice sounded hoarse. "He's alright."

Serenity rolled her eyes and turned back to the stove. "Do you want tea or hot chocolate?"

"…Chocolate."

Serenity leaned over the counter to grab the hot chocolate and glanced at the screen door.

Duke stood in the doorway, just beyond the light. In the silence, their eyes met. Serenity paused.

"Come in, Duke," she said eventually. "Tea or hot chocolate?"

Tristan sputtered.

Duke pushed the door open with a crooked grin. "Some green tea would be great." His hair was still wet from the shower, and clung to his sweatshirt as he reached toward a mug. After Serenity poured him his tea, he kept to the far side of the counter, his movements throwing eerie shadows on the wall.

"How long have you been there?" Tristan asked.

"Not long enough," Duke said, leaning back. "Sounds like I missed something important."

"You didn't," Tristan said. He took the full mug Serenity held out toward him and retreated to the far side of the kitchen, where he warily watched both his companions.

Duke winked at Serenity. He knew she would provide him with the details later. "So I'm just 'alright', huh?" he muttered. "Sounds like I've been flirting all wrong."

"Flirt with me and I'll pound your ass." Tristan said.

Duke smiled into his tea, and Serenity took the opportunity to hop up on the counter, where she took a sip of her hot chocolate. Tristan was on the other side of the room, and she could barely see him in the darkness. She looked back at Duke, who was twisting his hair in his fingers and staring at the counter like it was the most fascinating thing he'd ever seen.

"Duke, can I braid your hair?" she asked.

He look up, surprised. "I…I guess," he said, half-laughing. "I mean, if you really want to."

She motioned for him to come stand in front of her, and he circled the counter, grinning toward Tristan as he settled in against her knees.

Ignoring Tristan's huffs of contempt, Serenity started to part Duke's hair. It was wiry, and she paused.

"I thought it would be softer,"

"What?"

"Your hair."

"Oh...no. It's naturally like that." Duke tapped his fingers against his coffee mug, and while he was outwardly relaxed, Serenity could feel him jerk his head to repeatedly glance toward Tristan's corner.

"I've been wondering something," she said. "How can lighting up be a defense mechanism?"

"Huh?" Duke's fingers stopped tapping for a moment, then started again.

"The plankton," Serenity said. "If they light up, won't that just draw more predators toward them?"

"I don't know," Duke said. "That's a good question."

Serenity peered across the room. "Do you know, Tristan?"

Tristan's voice was heavy in the darkness. "Maybe it scares the hunters away."

"Who'd be scared away by a little light?" Duke said.

"You, apparently."

"I was never-"

Serenity put a hand on Duke's shoulder. "Maybe it's a call for help."

"From who?" Tristan asked. "Other plankton?"

"I don't know. Maybe." Serenity looked up. "Tristan, can you get me my coat? It's on the table."

"Why?" Tristan's question was justified: Serenity was still wearing Duke's coat.

"It has hair ties in it." Serenity said. "Please."

Tristan hesitated, then placed his cup down on the counter and moved past them into the dining room, where he shuffled around in the dark for a bit. When he returned, he held the coat out to Serenity, but she nodded toward her hands, still tangled in Duke's hair.

"Try the left pocket," she said. Tristan rolled his eyes and dug through the coat.

"She said left," Duke said.

"I know what she said!" Finally Tristan held up a pink hair tie, and Serenity took it, tied off the braid. and slung it over Duke's shoulder. He turned to pat her knee in appreciation before stepping aside and pulling himself up onto the counter next to her.

Folding the coat in his hands, Tristan leaned against the stove opposite them.

"Maybe it's vestigial." Duke said. When no one responded, he laughed a little. "The plankton. You know, like it used to help, but evolution went wrong somewhere and now it's kind of useless."

Serenity couldn't see his face, but she knew Duke was looking at Tristan. She picked up her coffee mug and took a sip. While she had been braiding Duke's hair, it had cooled to the perfect temperature.

"Vestigial," Tristan said.

"Yeah," Duke kicked the counter. "Aren't you the nature guy? I thought you were supposed to know these things."

"That's not nature, it's, like, biology."

"They're the same thing." Duke said. "Didn't you pay any attention in school?"

"Whatever it is," Serenity said. "It's still pretty."

Both boys turned to regard her.

"Is that our cue to compliment you?" Duke asked. "Because I think Tristan's going to kill me if I call you an angel one more time."

"Am not!"

"I think I've had my share of compliments for the day," Serenity said. "It was more of a cue to stop arguing."

Duke glanced at Tristan, and then back to Serenity. He took a deep breath.

"I guess it was pretty cool," he said.

Tristan sighed. "Yeah."

"Not at all tacky."

Tristan launched himself away from the counter, but Duke was laughing and Serenity was laughing and even Tristan smiled when he punched Duke in the shoulder.

"You're an asshole," he said.

"I know," Duke said. "Sorry."

Tristan shrugged. "You probably can't help it," he said. "So I guess it's alright."

Duke grinned at Tristan, and then as a unit they turned to look at Serenity.

"Better?" Duke asked.

"Better," Serenity said, taking a careful sip of hot chocolate. Over the course of their conversation, the distant crackle of the fire had faded until she could barely hear it at all, but she could still catch occasional murmurs in the darkness.

"Much better."

* * *

><p>AN: The "plankton" is called dinoflagellate, and occurs naturally all over the world. They light up when the water is disturbed, and the real function of the light is to summon predators to eat whatever's disturbing the water. So in a sense, Serenity's guess that it's "a call for help" is closest.  
>A longer commentary on the story can be found at http :  oxeyed . livejournal . com / 7493 . html


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